Proteins containing SH3 domains have been previously identified. For example, chimeric protein tyrosine kinases comprising SH3 and SH2 domains are disclosed in U.S. Pat. No. 5,439,819. Proteins including SH2 and SH3 domains have been found to be important in cell cycle processes, especially in signal transduction pathways. Cyclin dependent kinases comprising SH3 domains are well known participants in signal transduction processes. SH2 domains interact specifically with various proteins containing phosphotyrosine residues, whereas SH3 regions bind guanine nucleotide releasing factors, believed to be involved in important signaling pathways. Numerous SH3 and SH2 domains in molecules involved in signal transduction are discussed by Koch et al., Science, 252:668-674 (1991).
Interfering in the intracellular signal transduction pathways may provide a mechanism for numerous therapeutic applications. While several proteins have been identified that interfere with various signal transduction mechanisms, new active proteins are important in providing alternatives for therapy and drug development. The novel protein of the invention provides a heretofore unknown molecule which binds to the promoter region of a number of important genes and the Epstein-Barr virus.
A partial DNA sequence recently entered into the database called HSU618 has 95% homology over approximately 560 nucleotides to the TADG5 gene, The HSU618 sequence does not in itself contain an open reading frame and indeed contains stop codons in all frames of the sequence as entered into the database. The sequence does however have a high homology with the TADG5 gene starting at nucleotide 87 of the TADG5 sequence and covering the TADG5 sequence through approximately base 654. This indicates the sequence as entered may be part of the TADG5 gene. HSU618 is indicated to have the capacity to bind cyclin G proteins. The HSU618 sequence was submitted by F. Xu from the University of Southern California. Because the HSU618 fragment lacks an open reading frame it cannot be expressed to produce the corresponding protein fragment, nor could it be said to suggest the TADG5 protein amino acid sequence nor to disclose the isolated and purified DNA segment coding for the TADG5 protein.